SIST EN 61074:1998

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Determination of heats and temperatures of melting and crystallisation of electrical insulating materials by differential scanning calorimetry (IEC 61074:1991)Bestimmung von Wärmewerten und Temperaturen beim Schmelzen und Kristallisieren von Elektroisolierstoffen mittels dynamischer Differenz-KalorimetrieDétermination des chaleurs et températures de fusion et de cristallisation des matériaux isolants électriques par analyse calorimétrique différentielleDetermination of heats and temperatures of melting and crystallization of electrical insulating materials by differential scanning calorimetry29.035.01Izolacijski materiali na splošnoInsulating materials in generalICS:Ta slovenski standard je istoveten z:EN 61074:1993SIST EN 61074:1998en01-junij-1998SIST EN 61074:1998SLOVENSKI
STANDARD



SIST EN 61074:1998



SIST EN 61074:1998



SIST EN 61074:1998



NORMEINTERNATIONALEINTERNATIONALSTANDARDCEIIEC1074Première éditionFirst edition1991-09Détermination des chaleurs et températuresde fusion et de cristallisationdes matériaux isolants électriquespar exploration calorimétrique comparativeDetermination of heats and temperaturesof melting and crystallizationof electrical insulating materialsby differential scanning calorimetry© CE11991 Droits de reproduction réservés — Copyright — all rights reservedAucune partie de cette publication ne peut être reproduite niNo part of this publication may be reproduced or utilizedutilisée sous quelque forme que ce soit et par aucun procédé,in any form or by any means, electronic or mechanical,électronique ou mécanique, y compris la photocopie et lesincluding photocopying and microfilm, without permissionmicrofilms, sans raccord écrit de l'éditeur.in writing from the publisherBureau central de la Commission Electrotechnique Internationale 3, rue de Varembé Genève SuisseTéléfax: +41 22 919 0300e-mail: Inmail(Cl)IeC.ChIEC web site http://www.iec.chIEC•Commission Electrotechnique Internationale CODE PRIXLInternational Electrotechnical Commission PRICE CODEMcHlpyHapomiaR 3nenrpoTexHH4ecKaR KOMHCCHAPour prix, voir catalogue en vigueurFor price, see current catalogueSIST EN 61074:1998



1074©IEC- 3 -CONTENTSPageFOREWORD 5Clause1Scope 72Definitions73Significance 74 Test method 75Interference 96Precautions 97 Apparatus 98Sampling 119Calibration 1110 Procedure 1311Calculations 1512 Report 19Figures 22SIST EN 61074:1998



1074©IEC– 5 –INTERNATIONAL ELECTROTECHNICAL COMMISSIONDETERMINATION OF HEATS AND TEMPERATURESOF MELTING AND CRYSTALLIZATIONOF ELECTRICAL INSULATING MATERIALSBY DIFFERENTIAL SCANNING CALORIMETRYFOREWORD1)The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees onwhich all the National Committees having a special interest therein are represented, express, as nearly aspossible, an international consensus of opinion on the subjects dealt with.2)They have the form of recommendations for international use and they are accepted by the NationalCommittees in that sense.3)In order to promote international unification, the IEC expresses the wish that all National Committeesshould adopt the text of the IEC recommendation for their national rules in so far as national conditions willpermit. Any divergence between the IEC recommendation and the corresponding national rules should, asfar as possible, be clearly indicated in the latter.This International Standard has been prepared by Sub-Committee 15A: Short-time tests,of IEC Technical Committee No. 15: Insulating materials.The text of this standard is based on the following documents:DISReport on Voting
15A(CO)5915A(CO)62Full information on the voting for the approval of this standard can be found in the VotingReport indicated in the above table.SIST EN 61074:1998



1074©IEC- 7 -DETERMINATION OF HEATS AND TEMPERATURESOF MELTING AND CRYSTALLIZATIONOF ELECTRICAL INSULATING MATERIALSBY DIFFERENTIAL SCANNING CALORIMETRY1 Scope1.1 This method covers the determination of heats and temperatures of melting andcrystallization of electrical insulating materials by differential scanning calorimetry.1.2 The typical operating temperature range extends from -100 °C to +500 °C. Thetemperature range can be extended depending upon the instrumentation used.1.3 The method is generally applicable to thermally stable materials with well-definedexothermic and endothermic behaviour.2 DefinitionsDifferential scanning calorimetry (DSC): A technique in which the difference in energyinputs into a test material, referred to as "test specimen" thoughout the text, and areference material is measured as a function of temperature while the test specimen andthe reference material are subjected to a controlled temperature programme.NOTE - In this standard the terms "heat", "heat of fusion" and "heat of crystallization" used throughoutthe text are taken to be equivalent to the phrases "enthalpy" , "enthalpy of fusion" and "enthalpy of crystal-lization", respectively.3 Significance3.1 Differential scanning calorimetry provides a rapid method for the determination ofenthalpic changes accompanying first order transitions of materials.3.2 This test is useful for quality assurance, specification acceptance, and research.4 Test methodThe method consists of heating (or cooling) the test specimen at a controlled rate in acontrolled atmosphere through the region of melting (or crystallization). The differencein heat flow between the test specimen and the reference material due to energy changesin the material is continuously monitored and recorded as a function of temperature.A transition is marked by the absorption (or release) of energy by the test specimenSIST EN 61074:1998



1074©IEC- 9 -resulting in a corresponding endothermic (or exothermic) peak in the heating (or cooling)curve. Integration of the recorded peak area as a function of time results in a measure-ment of the energy of the transition. Observation of the position of the transition on thetemperature axis provides the necessary temperature information.5 InterferenceTest specimens that release volatiles on heating will change mass and this may invalidatethe test.6 Precautions6.1 This standard may involve the use of hazardous materials, operations andequipment. It is the responsibility of whoever uses this standard to establish appropriatesafety practices and to determine the applicability of regulatory limitations prior to use.6.2 Toxic or corrosive effluents, or both, may be released when heating the materialsand could be harmful to the personnel or apparatus.7 Apparatus7.1Differential scanning calorimeter having the following performance:a)heating or cooling rate up to 20 K/min;b)automatic recording of differential heat flow between the test specimen and thereference material;c)heat flow sensitivity to provide an accuracy of ±1 %;d)time base precision of ±1 % over the time base range from 0,1 to 2,0 min/cm (10,0to 0,5 cm/min) of chart;e)temperature sensitivity sufficient to provide a specimen temperature accurate to atleast ±0,1 K;f)preferred operating range of -100 °C to +500 °C.7.2 Planimeter, or other means of area measurement with an accuracy and precisionof ±0,1 %.7.3 Specimen holders, inert to the material being tested over the prescribed temperaturerange, composed of aluminium or other material of high thermal conductivity.SIST EN 61074:1998



1074©IEC- 11 -7.4 Dry nitrogen (at least 99,9 % pure) or other inert gas supply for purging purposes.The dew point of the selected gas shall be below the lowest operating temperature.7.5 Analytical balance, with a capacity greater than 15 mg, accurate to the nearest0,01 mg.8 Sampling8.1 Since small quantities of materials are used, it is essential that test specimens berepresentative of the material.8.2 Test specimens of powdered or granular materials shall be prepared by removingportions from various parts of the batch. These shall be mixed thoroughly to ensure a re-presentative test specimen for the determination. Coarse granular materials shall beground to reduce their size and achieve a more uniform mixture.Moulded or pelleted test specimens shall be cut with a microtome, razor blade, hypoder-mic punch, paper punch or cork borer to appropriate size, in a thickness or diameter andlength that will best fit the specimen holder and will approximate the desired weight in thesubsequent procedure.For film or sheet specimens thinner than 0,04 mm, slivers shall be cut to fit the test tubesor punch disks, if circular sample pans are used.NOTE - Grinding coarse granular materials to reduce their size can reduce crystallinity, which will affectthe melt transition.8.3 Unless otherwise specified, test specimens are measured as received. If some heattreatment is applied to the sample prior to analysis, this treatment should be noted in thereport. If some heat treatment is applied, record any mass loss as a result of that treat-ment. The measurements are only valid if the conditioning is precisely undertaken and thedetails recorded.9 Calibration9.1 Using the same heating rate, purge gas, and purge gas flow rate to be used forspecimens, calibrate the heat flow, time base, and temperature axis of the instrumentusing the instrument manufacturer's procedures with one or more of the following sub-stances having at least 99,9 % purity. For a temperature range c
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